const
   _POSIX_THREAD_KEYS_MAX = 128;
   PTHREAD_KEYS_MAX = 1024;
   _POSIX_THREAD_DESTRUCTOR_ITERATIONS = 4;
   PTHREAD_DESTRUCTOR_ITERATIONS = _POSIX_THREAD_DESTRUCTOR_ITERATIONS;
   _POSIX_THREAD_THREADS_MAX = 64;
   PTHREAD_THREADS_MAX = 1024;
   AIO_PRIO_DELTA_MAX = 20;
   PTHREAD_STACK_MIN = 16384;
   TIMER_MAX = 256;